Abrading apparatus



Aug. 23, 1932. s. N. JOHNSON ,ABRADING APPARATUS Filed Nov. 26, 1930 2 Sheets-Sheet l Aug. 23, 1932. N, JOHN ON 1,873,129

ABRADING APPARATUS Filed Nov. 26, 1930 2 Sheets-Sheet 2 any, 2

Patented Aug. 23, 1932 UETED- .s'rras I SIGURD N. JOHNSON, OF ANDERSON, INDIANA, ASSIGNOR TO DELCO-REMY CORPORA- TION, F ANDERSON, INDIANA, A CORPORATION. OF DELAWARE ABRADING APPARATUS Application filed November 26, 1930. Serial No; 498,336.

This invention relates toan apparatus for finishing the cylindrical surface of a commutator for a dynamo electric machine by applying thereto a flexible strip of abrasive material such as sand mutator is rotated.

It is one of the objects of the present invention to provide a commutator sand papering device which will permit the operation of finishing commutators to be performed more rapidly and economically than heretofore. This aim of the present invention is accomplished by providing a frame which carries an exposed portion of a strip of sand 1 paper and movable toward the commutator, while rotating, in order to press the sand paper against the surface of the commutator and movable away from the commutator to permit the removal of the same from the 2 work holder by which it is rotatably supported. The apparatus includes means for automatically feeding the strip of sand paper from a supply. roll so that each time the frame is'moved toward the commutator. a 2 fresh portion of paper will'have been eX- posed for operation upon the commutator.

Further objects and advantages of the present invention will be apparent from the following description, reference being had 30 to the accompanying drawings wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawings: Fig. 1 is a side elevation of a commutator 35 sand papering apparatus embodying the present invention. v

Figs. 2, 3 and 4 are sectional views taken respectively on the lines 22, 3-3 and 4-4 of Fig. 1. p 4 Fig. 5 isa view similar to Fig. 1 showing the sand paper holder frame separated from the commutator. v t

Fig. 6 is an end view looking in the direc tion of the arrow 6 of Fig.5..

Fig. 7 is a sectional view on the line 7 -.7 of Fig. 5. Fig. 8 is a sectional view on'the line 88 of Fig. 2.

In the drawings a commutator A mom- 59 ably supported by-a shaft B which'may be paper while the comthe armature shaft carrying the commutator.

C designates a fragment of'the frame of a lathe by which the shaft B is rotatably sup ported and driven. It is generally the practice to mount the commutator in a lathe and to machine the cylindrical surface of the commutator. concentric with the axis of its shaft and then to polish the commutator with a strip of abrasive paper. Accordingly the present invention comprises a stationary frame adapted to be attached'by screws 21 with the frame of the lathe. The frame 20 carries a stud 22 for supporting a roll of sand paper or other abrasive material 23. This roll is confined between discs 24, mounted upon the stud 22 and held in place bya thumb nut 25 having screw threaded engagement with one end of the stud 22. v V The frame 20 is provided with spaced cars rotatably supporting a trunnion pin 31 to which a screw 32 attaches a trunnion block 33 and the extension 34 of a movable frame 35 carrying an operating handle 36. The frame 35 carries a pivot stud which pivotally sup-1 ports a sand paper block frame 41 carrying a wooden sand paper block 42 having a cylindrical surface 43 conforming to thecurvature of'the commutator A.I The .block frame 41 is provided with a serrated 'cylindrical'sur face 44 located adjacent the cylindrical shank 45 of a headed pin 46retained bya cotter pin 47 in a hole provided by the frame 35. i The sand paper strip 50 passing from the supply roll 23 passes between the surface '44 of the block frame 41 and the shank 45 ofpin46 and thence around the corner 5'1'of the block 42, thence across the front face 43 of the block 42 and then around a tension bar 52 guided between ways 53 provided by the block frame 41. The tension bar 52 is'yieldingly urged outwardly by'the spring 54 confined in'a recess provided by the bar 52 and the frame 35. Outward movement of the bar 52 is limited by a pin 55 received by a block in the bar52;

The block frame 41 is yieldingly urged in a clockwise direction about its pivot stud 40 by a spring 60 surrounding a pin 61 attached at 62 to the block frame '41-and threadedly receiving a nut 63 which confines the spring 60 in a state of compression between the nut 63 and the frame 35. Thus the spring 60 tends to urge the serrated surface 44 against the sand paper strip 50 and thus tends to grip spring 7 7 toward the shaft 72. The spring 77 is maintained in a state of compression between the block 75 and the cover plate 78 attached to theframe 35 by screws 7 9. The

Y shafts 72 and 73 are attached respectively to 3 center line of the shafts 7 2 and ,7 3.

meshing gears 80 and 81.; Shaft 72 is, at tached to a ratchet wheel 82 which cooperates with a driving pawl83 pivoted upona screw 84 attached to aslide bar 85 guided for sliding movement bythe frame 35, A spring 86. confined between the frame 35 and a head 87 of the bar 85 urges the pawl 83 away from the Movement of; the bar 85 in this direction is limited by pin 88 striking the right hand end, of the slot 89provided by the frame 35. A helically coiled spring 90 surrounding the screw 84 has '0ne end held by an aperture in the screw, the other bearing against the pawl 83 and is so biased as to'cause the pawl 83 to be pressed against the ratchet 82. v A leaf spring 91 is fixed at one end to a-stud 92 attached to the frame 35, and its freeend bears against the ratchet 82 in order to prevent rotation o the ratchet in a clockwise direction.

The frame 20, provides a screw threaded ear 100 which receives an adjustable screw 101 secured in the desired position of adjustment by nut 102. As shown in F ig. 5 the head of'the screw 101 is engageable with a pin 61.

The frame is provided with ascrew threaded car 1 03 which receives an adjustable screw 104 secured in the desired position of adjustmentby nut 105. As shown in Fig. 5 the screw 104 is engageable with the head-87 of the slide bar 85.

' The manner of operatingthe sand papering apparatusis as follows. The strip 50 is pulled out from the supply roll 23. while the frame is maintained in the position shown in .Fig. 5 in which position the pin 61 engages with the screw 101 in order to cause the serrated; surface 44 of the block frame 41to be separated from the shank of pin 46. The strip is thenpassed around the corner 51 of the frame41 and then. across the free end of tension bar 52 as shown in Fig. 5 and tension 96 of plate 78. Then the operator graspsthe handle 36 to. movetheframe 35 counterclockwise in order to bring the sand paper against the commutator and to press it against the commutator by the pressure block 42. As the frame 35 comes toward the commutator the pin 61 is moved away from the screw 101 so as to permit the spring to move the frame clockwise about the pivot stud 40. Then. the sand paper strip is gripped between theserrated edge 44 andthe shank 45 of pin 46 so that no more sand paper can be pulled thereafter from the supply roll 23 during further movement of the block 42 against the commutator. As the strip 50 is caused to take an arcuate shape when pressed against the commutator, the tension bar 52 moves inwardly toward the frame 35 in. order that the sand paper strip moves to permit the engagement with the cylindrical surfaceofthe commutator. This is clearly shownin Fig. 1. .Theoperator maintains hold of the handle 36in order to press the sand paper against thecommutator to polish the surface. After the sand paperingoperation has been performed the operator moves thehandle in the opposite directionto cause the pin 61 to strike the screw 101 in the head 87 of the slide bar 85 to strike the screw104, thereby causing the block frame 41 to move counter'- clockwise about its pivot stud 40 and the pawl 83 to move toward the center line of-the feed roll shafts 72 and 73. In this way while the paper 50 is released fromb'eingjgripped between parts 44 and 45 the pawl 83 operates to turn the ratchet 82 in such direction as to cause the feed rolls 70 and 71 to movethe paper in a counterclockwisedirection With respect to the shaft 72 and in a clockwise direction with respect to the shaft 7 3. In this way the strip 50 is pulled from the supply roll 23 in order that a fresh portionthereof will be located adjacent the cylindrical sur-v face 43 of the sand paper 'presser'bloick 42.

The used paper passes'out through theslit of the extension 96 of-the plate 7 8' andmay be torn off by tearing acrossoneof the edges 95a of the slit 95. The apparatus is now ribbon of sheet abrasive material against the work, means for clamping the'ribbon against the pressing means while operating upon the work, means responsive to movement of the pressing means away from the work ferreleasing the clamping means, and-means for feeding the ribbon to the pressing means while unclamped relative thereto. A 5

2. Abrading apparatus comprising, in com operation upon 1 a bination, a stationary support, a swinging frame, a presser block carried thereby for pressing a portion of a ribbon of sheet abrasive material against the work, said presser block partially surrounding the workpiece, means for clamping the ribbon against the presser block while operating upon the Work, yielding means for stressing the ribbon while the latter is operating upon the workpiece, a pair of feed rolls carried by the frame, and means responsive to movement of the frame relative to the work for causing a fresh portion of the abrasive ribbon to be moved adj acent the presser block.

3. Abrading apparatus comprising, in combination, a stationary support, a' swinging frame, a presser block partially surrounding the workpiece for pressing a portion of a ribbon of abrasive material against the work, a spring urged plunger for stressing said ribbon while it is operating upon the wor piece so that slightly deformed portions of the latter are still subjected to the abrasive ribbon, a pair of feed rolls carried by the frame, and means responsive to movement of the frame relative to the work for causing a fresh portion of the abrasive ribbon to be moved adj acent the pressure block.

4. Abrading apparatus according to claim 3 further specified by having a presser block which is pivotally supported by the frame and has a serrated portion, said presser block being normally yieldably pressed with its serrated portion against the ribbon prior to its appliance upon the workpiece, and means for tilting said presser block while the frame is moving away from the workpiece, thereby removing its serrated portion from the ribbon.

5. Abra-ding apparatus comprising, in combination, a stationary support, a swinging frame, a presser block partially surrounding the workpiece and being pivotally supported by the frame, said block having a serrated portion and being normally yieldingly pressed with its serrated portion against the ribbon prior to its appliance upon the workpiece, a pair of feed rolls carried by the frame, means for turning said feed rolls, and adjustable stops on the support, one of them engaging said pressure block while the frame is withdrawing from the workpiece thereby tilting the pressure block so that its serrated portion removes from the ribbon, the other engaging and actuating the means for turning the feed rolls while the frame is withdrawing from the workpiece, said adjustable stops allowing for slight variations in the feeding of said ribbon.

6. Abrading apparatus comprising,in combination, a stationary support, a swinging frame, a presser block partially surrounding the workpiece and being pivotally supported .by the frame, said block having a serrated portion and being normally yieldingly pressed with its serrated portion against the ribbon prior to its appliance upon the workpiece, a spring urged plunger for stressing said ribbon while it is operating upon the workpiece so that slightly deformed portions of the latter are still subjected to the abrasive ribbon, a pair of feed rolls carried by the frame, means for turning said feed rolls, and adjustable stops on the support, one of them engaging said pressure block while the frame is withdrawing from the workpiece thereby tilting the pressure block so that its serrated portion removes from the ribbon, the other enga 'ng and actuating the means for turning t e feed rolls while the frame is withdrawing from the workpiece, said adjustable stops allowing for slight variations in the feeding of said ribbon.

In testimony whereof I hereto aflix my signature.

SIGURD N. JOHNSON. 

